This invention relates to a system for repairing scratches on optically-read discs, such as, for example, compact discs, digital video discs, etc. (often called “CD's” and “DVDs” respectively). More specifically, this invention provides a more efficient system for refurbishing the compact disc surface such that an optical reader, which, for example, may use a laser to read digital information stored on a compact disc, can read the digital information without the optical distortion caused by a scratch.
Typically, digitally recorded discs, known commonly as “CD” discs or “DVD” discs, contain audio or video information. The digital information is currently interpolated or read by an optical reader that uses one or more laser beams or other light amplified beams to read the digital information. The current state of the art of manufacture of these CD discs is such that they are comprised of a round disc composed of a synthetic material (e.g., plastic), with a typical diameter of approximately 4¾ inches and an approximate thickness of 1/16 inches. The disc has a center aperture typically approximately ⅝ inches in diameter for receiving a centering spindle in a playback apparatus. Digitally recorded material typically extends on one side of the disc, from about ¾ inches from the center aperture outward to within about ¼ inch of the peripheral end of the disc. A bearing area typically extends on the other side, in approximately the same dimensions, for bearing on a playback apparatus which spins the disc at high speed. The digital information is contained on a relatively thin layer of metallic material covered by a protective layer of the synthetic material, usually a plastic. A laser within the playback apparatus reads the digital information through the plastic layer. Recently (for example), optically-read discs include multi-layer laminated discs; and it is pointed out that describing discs generally herein is not intended to limit the technology of optically-read discs which is addressed herein. If the plastic layer becomes scratched or stained, the laser light will distort and not accurately read the digital information.
In the past, repair systems using diatomaceous earth and/or alumina oxides and/or silica oxides as abrasives have been contemplated for removing scratches from compact discs. However, these abrasives quickly degrade and lose effectiveness. Further abrasives such as diatomaceous earth, alumina oxides, and silica oxides do not provide a highly uniform particle size, which is desirable in abrading optical discs to remove scratches.